Introduces a backwards dataflow analysis pass to determine when a
certain register is always written to prior to being read in a
similar manner to SSA liveness but performed after RA which we can
use to determine when we can insert (last) on src regs on A7XX.
Passing VK-CTS: dEQP-VK.pipeline.*
Signed-off-by: Mark Collins <mark@igalia.com>
Co-Authored-by: Job Noorman <jnoorman@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25077>
Floating point SEL.CMOD may flush denorms to zero. We don't have enough
information at this point in compilation to know whether or not it is
safe to remove that.
Integer SEL or SEL without a conditional modifier is just a fancy
MOV. Those are always safe to eliminate.
See also 3f782cdd25.
Fixes: fab92fa1cb ("i965/fs: Optimize SEL with the same sources into a MOV.")
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34192>
The condition modifier on SEL means something completely different than
it means on MOV. On MOV it means to modify the flags based on the value
written to the destination. On SEL it means to compare the sources using
that mode and pick the result (i.e., as min() or max()) without
modifying the flags.
The resulting MOV should not have a condition modifier for the same
reason it (already) doesn't have a predicate. This bug was found by
inspection, so I added a unit test.
Fixes: fab92fa1cb ("i965/fs: Optimize SEL with the same sources into a MOV.")
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34192>
Floating point SEL.CMOD may flush denorms to zero. We don't have enough
information at this point in compilation to know whether or not it is
safe to remove that.
Integer SEL or SEL without a conditional modifier is just a fancy
MOV. Those are always safe to eliminate.
See also 3f782cdd25.
Fixes: fab92fa1cb ("i965/fs: Optimize SEL with the same sources into a MOV.")
No shader-db changes on any Intel platform.
fossil-db:
All Intel platforms had similar results. (Lunar Lake shown)
Totals:
Instrs: 209903490 -> 209903492 (+0.00%)
Cycle count: 30546025224 -> 30546021980 (-0.00%); split: -0.00%, +0.00%
Max live registers: 65516231 -> 65516235 (+0.00%)
Totals from 2 (0.00% of 706657) affected shaders:
Instrs: 3197 -> 3199 (+0.06%)
Cycle count: 361650 -> 358406 (-0.90%); split: -10.05%, +9.15%
Max live registers: 300 -> 304 (+1.33%)
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34192>
The condition modifier on SEL means something completely different than
it means on MOV. On MOV it means to modify the flags based on the value
written to the destination. On SEL it means to compare the sources using
that mode and pick the result (i.e., as min() or max()) without
modifying the flags.
The resulting MOV should not have a condition modifier for the same
reason it (already) doesn't have a predicate. This bug was found by
inspection, so I added a unit test.
No shader-db or shader-db changes on any Intel platform.
Fixes: fab92fa1cb ("i965/fs: Optimize SEL with the same sources into a MOV.")
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34192>
I was surprised this had any affect on Intel GPUs because we have been
unconditionally performing this optimization in the backend since June
2014.
Once that error is fixed (later in this MR), this change prevents a
couple dozen regressions in shader-db and around 90 regressions in
fossil-db. Many of the regressions in fossil-db were loss of SIMD32, and
that can be a big deal.
v2: Add 64-bit too. Suggested by Alyssa.
shader-db:
All Intel platforms had similar results. (Lunar Lake shown)
total instructions in shared programs: 16970141 -> 16970139 (<.01%)
instructions in affected programs: 40 -> 38 (-5.00%)
helped: 2 / HURT: 0
total cycles in shared programs: 914617580 -> 914617548 (<.01%)
cycles in affected programs: 3428 -> 3396 (-0.93%)
helped: 2 / HURT: 0
fossil-db:
All Intel platforms had similar results. (Lunar Lake shown)
Totals:
Cycle count: 30546028462 -> 30546025224 (-0.00%); split: -0.00%, +0.00%
Non SSA regs after NIR: 237017827 -> 237017731 (-0.00%)
Totals from 83 (0.01% of 706657) affected shaders:
Cycle count: 3042978 -> 3039740 (-0.11%); split: -0.13%, +0.02%
Non SSA regs after NIR: 78997 -> 78901 (-0.12%)
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34192>
Our strategy of covering the entire address space in buffer views
requires that we be able to create very large buffer views. The
pre-Maxwell texture unit doesn't allow for this.
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34542>
